Obtaining accurate timing of analog to digital converter samples in cellular modem

ABSTRACT

According to embodiments, an example method for determining an analog-to-digital converter (ADC) output timing in a user equipment may include operating a switch in a first mode to route a system clock from an oscillator to an input of the ADC and determining a first ADC output timing based on a first set of ADC samples generated by the ADC. The method may also include operating the switch in a second mode to route analog signals from a transceiver of the user equipment to the input of the ADC and obtaining a second set of ADC samples generated by the ADC based on the analog signals.

BACKGROUND 1. Field of Disclosure

The present disclosure relates generally to the field of wirelesscommunications, and more specifically to systems and methods forobtaining accurate timing of analog to digital convertor (ADC) samplesin a cellular modem for accurately measuring the timing of RF signalstraveling from a base station to a user equipment (e.g., a mobile deviceor cellphone).

2. Description of Related Art

In a mobile communication network, positioning of a user equipment (UE)can involve measurements of a reference radio frequency (RF) signaldetermined by a receiving device. The accuracy of the positioning isimpacted by the accuracy of the timing of these measurements. However,current wireless modems may have some uncertainty in theAnalog-to-Digital Converter (ADC) timing due to the accumulated delay inthe long ADC input clock generation path which will lead to theinaccuracy of the timing of these determined measurements and thus,negatively impact the accuracy of the positioning.

BRIEF SUMMARY

Techniques are provided in which accurate timing of analog to digitalconvertor (ADC) samples in a cellular modem is obtained for accuratelydetermining the measurements for positioning, based on the received RFsignal.

An example method for determining an analog-to-digital converter (ADC)output timing in a user equipment may include operating a switch in afirst mode to route a system clock from an oscillator to an input of theADC and determining a first ADC output timing based on a first set ofADC samples generated by the ADC. The method may also include operatingthe switch in a second mode to route analog signals from a transceiverof the user equipment to the input of the ADC and obtaining a second setof ADC samples generated by the ADC based on the analog signals.

An example device may include one or more transceivers configured toreceive analog signals and an analog-to-digital converter (ADC)configured to generate ADC samples. The device may also include one ormore processors configured to operate a switch in a first mode to routea system clock from an oscillator to an input of the ADC and determine afirst ADC output timing based on a first set of ADC samples generated bythe ADC. The one or more processors may also be configured to operatethe switch in a second mode to route analog signals from a transceiverto the input of the ADC and obtain a second set of ADC samples generatedby the ADC based on the analog signals.

An example UE may include means for operating a switch in a first modeto route a system clock from an oscillator to an input of the ADC andmeans for determining a first ADC output timing based on a first set ofADC samples generated by the ADC. The UE may also include means foroperating the switch in a second mode to route analog signals from atransceiver of the user equipment to the input of the ADC and means forobtaining a second set of ADC samples generated by the ADC based on theanalog signals.

This summary is neither intended to identify key or essential featuresof the claimed subject matter, nor is it intended to be used inisolation to determine the scope of the claimed subject matter. Thesubject matter should be understood by reference to appropriate portionsof the entire specification of this disclosure, any or all drawings, andeach claim. The foregoing, together with other features and examples,will be described in more detail below in the following specification,claims, and accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a positioning system, according to an embodiment.

FIG. 2 is a diagram of a 5th Generation (5G) New Radio (NR) positioningsystem, illustrating an embodiment of a positioning system (e.g., thepositioning system of FIG. 1 ) implemented within a 5G NR communicationsystem.

FIG. 3 illustrates an example sampled cross-correlation between awaveform transmitted by a base station and a waveform received by a UE.

FIGS. 4A and 4B illustrate an existing ADC sampling system and thecorresponding timing diagrams of the clock signals.

FIG. 5 is a diagram illustrating an example ADC sampling systemaccording to an embodiment.

FIG. 6 is a flow chart of determining an ADC output timing in a UE,according to an embodiment.

FIGS. 7A and 7B illustrate another example ADC sampling system and thecorresponding timing diagrams for the clock signals according to anembodiment.

FIG. 8 is a flow chart of determining an ADC output timing in a UE,according to an embodiment.

FIG. 9 is a block diagram of an embodiment of a UE, which can beutilized in embodiments as described herein.

Like reference symbols in the various drawings indicate like elements,in accordance with certain example implementations. In addition,multiple instances of an element may be indicated by following a firstnumber for the element with a letter or a hyphen and a second number.For example, multiple instances of an element 110 may be indicated as110-1, 110-2, 110-3 etc. or as 110 a, 110 b, 110 c, etc. When referringto such an element using only the first number, any instance of theelement is to be understood (e.g., element 110 in the previous examplewould refer to elements 110-1, 110-2, and 110-3 or to elements 110 a,110 b, and 110 c).

DETAILED DESCRIPTION

The following description is directed to certain implementations for thepurposes of describing innovative aspects of various embodiments.However, a person having ordinary skill in the art will readilyrecognize that the teachings herein can be applied in a multitude ofdifferent ways. The described implementations may be implemented in anydevice, system, or network that is capable of transmitting and receivingradio frequency (RF) signals according to any communication standard,such as any of the Institute of Electrical and Electronics Engineers(IEEE) IEEE 802.11 standards (including those identified as Wi-Fi®technologies), the Bluetooth® standard, code division multiple access(CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), Global System for Mobile communications (GSM),GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment(EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA),Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B,High Rate Packet Data (HRPD), High Speed Packet Access (HSPA), HighSpeed Downlink Packet Access (HSDPA), High Speed Uplink Packet Access(HSUPA), Evolved High Speed Packet Access (HSPA+), Long Term Evolution(LTE), Advanced Mobile Phone System (AMPS), or other known signals thatare used to communicate within a wireless, cellular or internet ofthings (IoT) network, such as a system utilizing 3G, 4G, 5G, 6G, orfurther implementations thereof, technology.

As used herein, an “RF signal” comprises an electromagnetic wave thattransports information through the space between a transmitter (ortransmitting device) and a receiver (or receiving device). As usedherein, a transmitter may transmit a single “RF signal” or multiple “RFsignals” to a receiver. However, the receiver may receive multiple “RFsignals” corresponding to each transmitted RF signal due to thepropagation characteristics of RF signals through multiple channels orpaths.

Additionally, unless otherwise specified, references to “referencesignals,” “positioning reference signals,” “reference signals forpositioning,” and the like may be used to refer to signals used forpositioning of a user equipment (UE). As described in more detailherein, such signals may comprise any of a variety of signal types butmay not necessarily be limited to a Positioning Reference Signal (PRS)as defined in relevant wireless standards.

In wireless communications (e.g., based on Fifth Generation (5G) NewRadio (NR) mobile communication network), the location of a target UEcan be determined based on the wireless propagation delay of a signal(e.g., a reference signal) sent from or received by the target UE. Thewireless propagation delay of the signal is a time difference betweenthe transmission of the signal by a transmitting device and the receiptof the signal at a receiving device (e.g., determined based on usingsampled cross-correlation to determine a total delay between thetransmitted waveform and the received waveform). The wirelesspropagation delay of a signal sent by a base station and received by aUE may be determined, for example, from an RTT measurement of thesignal, in which the UE measures a time at which the signal is receivedand further transmits a response signal. The accuracy of a determinedpropagation time may be impacted by an accuracy of a determination ofwhen the signal was received by the UE.

An ADC is an important processing component in UE processing modules(e.g., the modem) configured to convert analog signals received from thereceiver circuits to digital signals (e.g., sampling) based on an ADCclock (e.g., ADC input clock) for storing (e.g., capture samples in afirst in first out (FIFO) memory/buffer) and/or further processing.Existing UE modems have uncertainty in determining the ADC output timing(e.g., the timing of the ADC output samples) due to the accumulateddelay in the long ADC input clock generation path (e.g., generated basedon a system clock). Accordingly, an accurate determination of outputtiming in ADC sampling module (e.g., the timing difference between thesystem clock and the ADC input clock) can help ensure an accuratedetermination of the location of a target UE.

As disclosed herein, in some embodiments, a switch is added at the inputterminal of the ADC in addition to an existing ADC sampling system.Specifically, the ADC sampling module may first function in a timingdetermination mode (e.g., the switch is at a first position), where thesystem clock (e.g., generated by an oscillator and used as the referenceclock) is directly routed to an input terminal of the ADC. The modem(e.g., a processor) may determine a first ADC output timing based onanalyzing a first set of output samples generated using the system clockas the input signal. Then the ADC sampling module may function in aregular working mode (e.g., the switch is at a second position), whereanalog signals (e.g., RF signals) received by a transceiver of the UEare routed to the input terminal of the ADC and the ADC is configured togenerate a second set of ADC samples using the analog signals as theinput signal. Accordingly, the timing of the second set of samples(e.g., generated based on analog signals received from the transceiver)may be determined based on the first ADC output timing (e.g., the ADCoutput timing of the first set of output samples generated using thesystem clock).

In some other embodiments, an ADC output timing determining module maybe added in addition to an existing ADC sampling system. The ADC outputtiming determining module may include a counter configured to determinethe ADC output timing. The counter may take both the system clock andthe ADC output clock as inputs to determine the timing of the ADC outputsamples, e.g., determining the difference between the ADC output clockand the system clock (e.g., using the system clock as the reference).

Additional details will follow after an initial description of relevantsystems and technologies.

FIG. 1 is a simplified illustration of a positioning system 100 in whicha UE 105, location server 160, and/or other components of thepositioning system 100 can use the techniques provided herein fordetermining an estimated location of UE 105, specifically, fordetermining an ADC output timing in UE 105 according to an embodiment.The techniques described herein may be implemented by one or morecomponents of the positioning system 100. The positioning system 100 caninclude: a UE 105; one or more satellites 110 (also referred to as spacevehicles (SVs)) for a Global Navigation Satellite System (GNSS) such asthe Global Positioning System (GPS), GLONASS, Galileo or Beidou; basestations 120; access points (APs) 130; location server 160; network 170;and external client 180. Generally put, the positioning system 100 canestimate a location of the UE 105 based on RF signals received by and/orsent from the UE 105 and known locations of other components (e.g., GNSSsatellites 110, base stations 120, APs 130) transmitting and/orreceiving the RF signals. Additional details regarding particularlocation estimation techniques are discussed in more detail with regardto FIG. 2 .

It should be noted that FIG. 1 provides only a generalized illustrationof various components, any or all of which may be utilized asappropriate, and each of which may be duplicated as necessary.Specifically, although only one UE 105 is illustrated, it will beunderstood that many UEs (e.g., hundreds, thousands, millions, etc.) mayutilize the positioning system 100. Similarly, the positioning system100 may include a larger or smaller number of base stations 120 and/orAPs 130 than illustrated in FIG. 1 . The illustrated connections thatconnect the various components in the positioning system 100 comprisedata and signaling connections which may include additional(intermediary) components, direct or indirect physical and/or wirelessconnections, and/or additional networks. Furthermore, components may berearranged, combined, separated, substituted, and/or omitted, dependingon desired functionality. In some embodiments, for example, the externalclient 180 may be directly connected to location server 160. A person ofordinary skill in the art will recognize many modifications to thecomponents illustrated.

Depending on desired functionality, the network 170 may comprise any ofa variety of wireless and/or wireline networks. The network 170 can, forexample, comprise any combination of public and/or private networks,local and/or wide-area networks, and the like. Furthermore, the network170 may utilize one or more wired and/or wireless communicationtechnologies. In some embodiments, the network 170 may comprise acellular or other mobile network, a wireless local area network (WLAN),a wireless wide-area network (WWAN), and/or the Internet, for example.Examples of network 170 include a Long-Term Evolution (LTE) wirelessnetwork, a Fifth Generation (5G) wireless network (also referred to asNew Radio (NR) wireless network or 5G NR wireless network), a Wi-FiWLAN, and the Internet. LTE, 5G and NR are wireless technologiesdefined, or being defined, by the 3rd Generation Partnership Project(3GPP). Network 170 may also include more than one network and/or morethan one type of network.

The base stations 120 and access points (APs) 130 may be communicativelycoupled to the network 170. In some embodiments, the base station 120 smay be owned, maintained, and/or operated by a cellular networkprovider, and may employ any of a variety of wireless technologies, asdescribed herein below. Depending on the technology of the network 170,a base station 120 may comprise a node B, an Evolved Node B (eNodeB oreNB), a base transceiver station (BTS), a radio base station (RBS), anNR NodeB (gNB), a Next Generation eNB (ng-eNB), or the like. A basestation 120 that is a gNB or ng-eNB may be part of a Next GenerationRadio Access Network (NG-RAN) which may connect to a 5G Core Network(5GC) in the case that Network 170 is a 5G network. An AP 130 maycomprise a Wi-Fi AP or a Bluetooth® AP or an AP having cellularcapabilities (e.g., 4G LTE and/or 5G NR), for example. Thus, UE 105 cansend and receive information with network-connected devices, such aslocation server 160, by accessing the network 170 via a base station 120using a first communication link 133. Additionally or alternatively,because APs 130 also may be communicatively coupled with the network170, UE 105 may communicate with network-connected andInternet-connected devices, including location server 160, using asecond communication link 135, or via one or more other UEs 145.

As used herein, the term “base station” may generically refer to asingle physical transmission point, or multiple co-located physicaltransmission points, which may be located at a base station 120. ATransmission Reception Point (TRP) (also known as transmit/receivepoint) corresponds to this type of transmission point, and the term“TRP” may be used interchangeably herein with the terms “gNB,” “ng-eNB,”and “base station.” In some cases, a base station 120 may comprisemultiple TRPs - e.g. with each TRP associated with a different antennaor a different antenna array for the base station 120. Physicaltransmission points may comprise an array of antennas of a base station120 (e.g., as in a Multiple Input-Multiple Output (MIMO) system and/orwhere the base station employs beamforming). The term “base station” mayadditionally refer to multiple non-co-located physical transmissionpoints, the physical transmission points may be a Distributed AntennaSystem (DAS) (a network of spatially separated antennas connected to acommon source via a transport medium) or a Remote Radio Head (RRH) (aremote base station connected to a serving base station).

As used herein, the term “cell” may generically refer to a logicalcommunication entity used for communication with a base station 120, andmay be associated with an identifier for distinguishing neighboringcells (e.g., a Physical Cell Identifier (PCID), a Virtual CellIdentifier (VCID)) operating via the same or a different carrier. Insome examples, a carrier may support multiple cells, and different cellsmay be configured according to different protocol types (e.g.,Machine-Type Communication (MTC), Narrowband Internet-of-Things(NB-IoT), Enhanced Mobile Broadband (eMBB), or others) that may provideaccess for different types of devices. In some cases, the term “cell”may refer to a portion of a geographic coverage area (e.g., a sector)over which the logical entity operates.

The location server 160 may comprise a server and/or other computingdevice configured to determine an estimated location of UE 105 and/orprovide data (e.g., “assistance data”) to UE 105 to facilitate locationmeasurement and/or location determination by UE 105. According to someembodiments, location server 160 may comprise a Home Secure User PlaneLocation (SUPL) Location Platform (H-SLP), which may support the SUPLuser plane (UP) location solution defined by the Open Mobile Alliance(OMA) and may support location services for UE 105 based on subscriptioninformation for UE 105 stored in location server 160. In someembodiments, the location server 160 may comprise, a Discovered SLP(D-SLP) or an Emergency SLP (E-SLP). The location server 160 may alsocomprise an Enhanced Serving Mobile Location Center (E-SMLC) thatsupports location of UE 105 using a control plane (CP) location solutionfor LTE radio access by UE 105. The location server 160 may furthercomprise a Location Management Function (LMF) that supports location ofUE 105 using a control plane (CP) location solution for NR or LTE radioaccess by UE 105.

In a CP location solution, signaling to control and manage the locationof UE 105 may be exchanged between elements of network 170 and with UE105 using existing network interfaces and protocols and as signalingfrom the perspective of network 170. In a UP location solution,signaling to control and manage the location of UE 105 may be exchangedbetween location server 160 and UE 105 as data (e.g. data transportedusing the Internet Protocol (IP) and/or Transmission Control Protocol(TCP)) from the perspective of network 170.

As previously noted (and discussed in more detail below), the estimatedlocation of UE 105 may be based on measurements of RF signals sent fromand/or received by the UE 105. In particular, these measurements canprovide information regarding the relative distance and/or angle of theUE 105 from one or more components in the positioning system 100 (e.g.,GNSS satellites 110, APs 130, base stations 120). The estimated locationof the UE 105 can be estimated geometrically (e.g., usingmultiangulation and/or multilateration), based on the distance and/orangle measurements, along with known position of the one or morecomponents.

Although terrestrial components such as APs 130 and base stations 120may be fixed, embodiments are not so limited. Mobile components may beused. For example, in some embodiments, a location of the UE 105 may beestimated at least in part based on measurements of RF signals 140communicated between the UE 105 and one or more other UEs 145, which maybe mobile or fixed. When or more other UEs 145 are used in the positiondetermination of a particular UE 105, the UE 105 for which the positionis to be determined may be referred to as the “target UE,” and each ofthe one or more other UEs 145 used may be referred to as an “anchor UE.”For position determination of a target UE, the respective positions ofthe one or more anchor UEs may be known and/or jointly determined withthe target UE. Direct communication between the one or more other UEs145 and UE 105 may comprise sidelink and/or similar Device-to-Device(D2D) communication technologies. Sidelink, which is defined by 3GPP, isa form of D2D communication under the cellular-based LTE and NRstandards.

An estimated location of UE 105 can be used in a variety ofapplications - e.g. to assist direction finding or navigation for a userof UE 105 or to assist another user (e.g. associated with externalclient 180) to locate UE 105. A “location” is also referred to herein asa “location estimate”, “estimated location”, “location”, “position”,“position estimate”, “position fix”, “estimated position”, “locationfix” or “fix”. The process of determining a location may be referred toas “positioning,” “position determination,” “location determination,” orthe like. A location of UE 105 may comprise an absolute location of UE105 (e.g. a latitude and longitude and possibly altitude) or a relativelocation of UE 105 (e.g. a location expressed as distances north orsouth, east or west and possibly above or below some other known fixedlocation (including, e.g., the location of a base station 120 or AP 130)or some other location such as a location for UE 105 at some knownprevious time, or a location of another UE 145 at some known previoustime). A location may be specified as a geodetic location comprisingcoordinates which may be absolute (e.g. latitude, longitude andoptionally altitude), relative (e.g. relative to some known absolutelocation) or local (e.g. X, Y and optionally Z coordinates according toa coordinate system defined relative to a local area such a factory,warehouse, college campus, shopping mall, sports stadium or conventioncenter). A location may instead be a civic location and may thencomprise one or more of a street address (e.g. including names or labelsfor a country, state, county, city, road and/or street, and/or a road orstreet number), and/or a label or name for a place, building, portion ofa building, floor of a building, and/or room inside a building etc. Alocation may further include an uncertainty or error indication, such asa horizontal and possibly vertical distance by which the location isexpected to be in error or an indication of an area or volume (e.g. acircle or ellipse) within which UE 105 is expected to be located withsome level of confidence (e.g. 95% confidence).

The external client 180 may be a web server or remote application thatmay have some association with UE 105 (e.g. may be accessed by a user ofUE 105) or may be a server, application, or computer system providing alocation service to some other user or users which may include obtainingand providing the location of UE 105 (e.g. to enable a service such asfriend or relative finder, or child or pet location). Additionally oralternatively, the external client 180 may obtain and provide thelocation of UE 105 to an emergency services provider, government agency,etc.

As previously noted, the example positioning system 100 can beimplemented using a wireless communication network, such as an LTE-basedor 5G NR-based network. FIG. 2 shows a diagram of a 5G NR positioningsystem 200, illustrating an embodiment of a positioning system (e.g.,positioning system 100) implementing 5G NR. The 5G NR positioning system200 may be configured to determine the location of a UE 105 by usingaccess nodes, which may include NR NodeB (gNB) 210-1 and 210-2(collectively and generically referred to herein as gNBs 210), ng-eNB214, and/or WLAN 216 to implement one or more positioning methods. ThegNBs 210 and/or the ng-eNB 214 may correspond with base stations 120 ofFIG. 1 , and the WLAN 216 may correspond with one or more access points130 of FIG. 1 . Optionally, the 5G NR positioning system 200additionally may be configured to determine the location of a UE 105 byusing an LMF 220 (which may correspond with location server 160) toimplement the one or more positioning methods. Here, the 5G NRpositioning system 200 comprises a UE 105, and components of a 5G NRnetwork comprising a Next Generation (NG) Radio Access Network (RAN)(NG-RAN) 235 and a 5G Core Network (5G CN) 240. A 5G network may also bereferred to as an NR network; NG-RAN 235 may be referred to as a 5G RANor as an NR RAN; and 5G CN 240 may be referred to as an NG Core network.The 5G NR positioning system 200 may further utilize information fromGNSS satellites 110 from a GNSS system like Global Positioning System(GPS) or similar system (e.g. GLONASS, Galileo, Beidou, Indian RegionalNavigational Satellite System (IRNSS)). Additional components of the 5GNR positioning system 200 are described below. The 5G NR positioningsystem 200 may include additional or alternative components.

It should be noted that FIG. 2 provides only a generalized illustrationof various components, any or all of which may be utilized asappropriate, and each of which may be duplicated or omitted asnecessary. Specifically, although only one UE 105 is illustrated, itwill be understood that many UEs (e.g., hundreds, thousands, millions,etc.) may utilize the 5G NR positioning system 200. Similarly, the 5G NRpositioning system 200 may include a larger (or smaller) number of GNSSsatellites 110, gNBs 210, ng-eNBs 214, Wireless Local Area Networks(WLANs) 216, Access and mobility Management Functions (AMF)s 215,external clients 230, and/or other components. The illustratedconnections that connect the various components in the 5G NR positioningsystem 200 include data and signaling connections which may includeadditional (intermediary) components, direct or indirect physical and/orwireless connections, and/or additional networks. Furthermore,components may be rearranged, combined, separated, substituted, and/oromitted, depending on desired functionality.

The UE 105 may comprise and/or be referred to as a device, a mobiledevice, a wireless device, a mobile terminal, a terminal, a mobilestation (MS), a Secure User Plane Location (SUPL)-Enabled Terminal(SET), or by some other name. Moreover, UE 105 may correspond to acellphone, smartphone, laptop, tablet, personal data assistant (PDA),navigation device, Internet of Things (IoT) device, or some otherportable or moveable device. Typically, though not necessarily, the UE105 may support wireless communication using one or more Radio AccessTechnologies (RATs) such as using GSM, CDMA, W-CDMA, LTE, High RatePacket Data (HRPD), IEEE 802.11 Wi-Fi®, Bluetooth, WorldwideInteroperability for Microwave Access (WiMAX™), 5G NR (e.g., using theNG-RAN 235 and 5G CN 240), etc. The UE 105 may also support wirelesscommunication using a WLAN 216 which (like the one or more RATs, and aspreviously noted with respect to FIG. 1 ) may connect to other networks,such as the Internet. The use of one or more of these RATs may allow theUE 105 to communicate with an external client 230 (e.g., via elements of5G CN 240 not shown in FIG. 2 , or possibly via a Gateway MobileLocation Center (GMLC) 225) and/or allow the external client 230 toreceive location information regarding the UE 105 (e.g., via the GMLC225). The external client 230 of FIG. 2 may correspond to externalclient 180 of FIG. 1 , as implemented in or communicatively coupled witha 5G NR network.

The UE 105 may include a single entity or may include multiple entities,such as in a personal area network where a user may employ audio, videoand/or data I/O devices, and/or body sensors and a separate wireline orwireless modem. An estimate of a location of the UE 105 may be referredto as a location, location estimate, location fix, fix, position,position estimate, or position fix, and may be geodetic, thus providinglocation coordinates for the UE 105 (e.g., latitude and longitude),which may or may not include an altitude component (e.g., height abovesea level, height above or depth below ground level, floor level orbasement level). Alternatively, a location of the UE 105 may beexpressed as a civic location (e.g., as a postal address or thedesignation of some point or small area in a building such as aparticular room or floor). A location of the UE 105 may also beexpressed as an area or volume (defined either geodetically or in civicform) within which the UE 105 is expected to be located with someprobability or confidence level (e.g., 67%, 95%, etc.). A location ofthe UE 105 may further be a relative location comprising, for example, adistance and direction or relative X, Y (and Z) coordinates definedrelative to some origin at a known location which may be definedgeodetically, in civic terms, or by reference to a point, area, orvolume indicated on a map, floor plan or building plan. In thedescription contained herein, the use of the term location may compriseany of these variants unless indicated otherwise. When computing thelocation of a UE, it is common to solve for local X, Y, and possibly Zcoordinates and then, if needed, convert the local coordinates intoabsolute ones (e.g. for latitude, longitude and altitude above or belowmean sea level).

Base stations in the NG-RAN 235 shown in FIG. 2 may correspond to basestations 120 in FIG. 1 and may include gNBs 210. Pairs of gNBs 210 inNG-RAN 235 may be connected to one another (e.g., directly as shown inFIG. 2 or indirectly via other gNBs 210). The communication interfacebetween base stations (gNBs 210 and/or ng-eNB 214) may be referred to asan Xn interface 237. Access to the 5G network is provided to UE 105 viawireless communication between the UE 105 and one or more of the gNBs210, which may provide wireless communications access to the 5G CN 240on behalf of the UE 105 using 5G NR. The wireless interface between basestations (gNBs 210 and/or ng-eNB 214) and the UE 105 may be referred toas a Uu interface 239. 5G NR radio access may also be referred to as NRradio access or as 5G radio access. In FIG. 2 , the serving gNB for UE105 is assumed to be gNB 210-1, although other gNBs (e.g. gNB 210-2) mayact as a serving gNB if UE 105 moves to another location or may act as asecondary gNB to provide additional throughput and bandwidth to UE 105.

Base stations in the NG-RAN 235 shown in FIG. 2 may also or insteadinclude a next generation evolved Node B, also referred to as an ng-eNB,214. Ng-eNB 214 may be connected to one or more gNBs 210 in NG-RAN235-e.g., directly or indirectly via other gNBs 210 and/or otherng-eNBs. An ng-eNB 214 may provide LTE wireless access and/or evolvedLTE (eLTE) wireless access to UE 105. Some gNBs 210 (e.g., gNB 210-2)and/or ng-eNB 214 in FIG. 2 may be configured to function aspositioning-only beacons which may transmit signals (e.g., PositioningReference Signal (PRS)) and/or may broadcast assistance data to assistpositioning of UE 105 but may not receive signals from UE 105 or fromother UEs. Some gNBs 210 (e.g., gNB 210-2 and/or another gNB not shown)and/or ng-eNB 214 may be configured to function as detecting-only nodesmay scan for signals containing, e.g., PRS data, assistance data, orother location data. Such detecting-only nodes may not transmit signalsor data to UEs but may transmit signals or data (relating to, e.g., PRS,assistance data, or other location data) to other network entities(e.g., one or more components of 5G CN 240, external client 230, or acontroller) which may receive and store or use the data for positioningof at least UE 105. It is noted that while only one ng-eNB 214 is shownin FIG. 2 , some embodiments may include multiple ng-eNBs 214. Basestations (e.g., gNBs 210 and/or ng-eNB 214) may communicate directlywith one another via an Xn communication interface. Additionally, oralternatively, base stations may communicate directly or indirectly withother components of the 5G NR positioning system 200, such as the LMF220 and AMF 215.

5G NR positioning system 200 may also include one or more WLANs 216which may connect to a Non-3GPP InterWorking Function (N3IWF) 250 in the5G CN 240 (e.g., in the case of an untrusted WLAN 216). For example, theWLAN 216 may support IEEE 802.11 Wi-Fi access for UE 105 and maycomprise one or more Wi-Fi APs (e.g., APs 130 of FIG. 1 ). Here, theN3IWF 250 may connect to other elements in the 5G CN 240 such as AMF215. In some embodiments, WLAN 216 may support another RAT such asBluetooth. The N3IWF 250 may provide support for secure access by UE 105to other elements in 5G CN 240 and/or may support interworking of one ormore protocols used by WLAN 216 and UE 105 to one or more protocols usedby other elements of 5G CN 240 such as AMF 215. For example, N3IWF 250may support IPSec tunnel establishment with UE 105, termination ofIKEv2/IPSec protocols with UE 105, termination of N2 and N3 interfacesto 5G CN 240 for control plane and user plane, respectively, relaying ofuplink (UL) and downlink (DL) control plane Non-Access Stratum (NAS)signaling between UE 105 and AMF 215 across an N1 interface. In someother embodiments, WLAN 216 may connect directly to elements in 5G CN240 (e.g. AMF 215 as shown by the dashed line in FIG. 2 ) and not viaN3IWF 250. For example, direct connection of WLAN 216 to 5GCN 240 mayoccur if WLAN 216 is a trusted WLAN for 5GCN 240 and may be enabledusing a Trusted WLAN Interworking Function (TWIF) (not shown in FIG. 2 )which may be an element inside WLAN 216. It is noted that while only oneWLAN 216 is shown in FIG. 2 , some embodiments may include multipleWLANs 216.

Access nodes may comprise any of a variety of network entities enablingcommunication between the UE 105 and the AMF 215. As noted, this caninclude gNBs 210, ng-eNB 214, WLAN 216, and/or other types of cellularbase stations. However, access nodes providing the functionalitydescribed herein may additionally or alternatively include entitiesenabling communications to any of a variety of RATs not illustrated inFIG. 2 , which may include non-cellular technologies. Thus, the term“access node,” as used in the embodiments described herein below, mayinclude but is not necessarily limited to a gNB 210, ng-eNB 214 or WLAN216.

In some embodiments, an access node, such as a gNB 210, ng-eNB 214,and/or WLAN 216 (alone or in combination with other components of the 5GNR positioning system 200), may be configured to, in response toreceiving a request for location information from the LMF 220, obtainlocation measurements of uplink (UL) signals received from the UE 105)and/or obtain downlink (DL) location measurements from the UE 105 thatwere obtained by UE 105 for DL signals received by UE 105 from one ormore access nodes. As noted, while FIG. 2 depicts access nodes (gNB 210,ng-eNB 214, and WLAN 216) configured to communicate according to 5G NR,LTE, and Wi-Fi communication protocols, respectively, access nodesconfigured to communicate according to other communication protocols maybe used, such as, for example, a Node B using a Wideband Code DivisionMultiple Access (WCDMA) protocol for a Universal MobileTelecommunications Service (UMTS) Terrestrial Radio Access Network(UTRAN), an eNB using an LTE protocol for an Evolved UTRAN (E-UTRAN), ora Bluetooth® beacon using a Bluetooth protocol for a WLAN. For example,in a 4G Evolved Packet System (EPS) providing LTE wireless access to UE105, a RAN may comprise an E-UTRAN, which may comprise base stationscomprising eNBs supporting LTE wireless access. A core network for EPSmay comprise an Evolved Packet Core (EPC). An EPS may then comprise anE-UTRAN plus an EPC, where the E-UTRAN corresponds to NG-RAN 235 and theEPC corresponds to 5GCN 240 in FIG. 2 . The methods and techniquesdescribed herein for obtaining a civic location for UE 105 may beapplicable to such other networks.

The gNBs 210 and ng-eNB 214 can communicate with an AMF 215, which, forpositioning functionality, communicates with an LMF 220. The AMF 215 maysupport mobility of the UE 105, including cell change and handover of UE105 from an access node (e.g., gNB 210, ng-eNB 214, or WLAN 216) of afirst RAT to an access node of a second RAT. The AMF 215 may alsoparticipate in supporting a signaling connection to the UE 105 andpossibly data and voice bearers for the UE 105. The LMF 220 may supportpositioning of the UE 105 using a CP location solution when UE 105accesses the NG-RAN 235 or WLAN 216 and may support position proceduresand methods, including UE assisted/UE based and/or network basedprocedures/methods, such as Assisted GNSS (A-GNSS), Observed TimeDifference Of Arrival (OTDOA) (which may be referred to in NR as TimeDifference Of Arrival (TDOA)), Real Time Kinematic (RTK), Precise PointPositioning (PPP), Differential GNSS (DGNSS), Enhance Cell ID (ECID),angle of arrival (AoA), angle of departure (AoD), WLAN positioning,round trip signal propagation delay (RTT), multi-cell RTT, and/or otherpositioning procedures and methods. The LMF 220 may also processlocation service requests for the UE 105, e.g., received from the AMF215 or from the GMLC 225. The LMF 220 may be connected to AMF 215 and/orto GMLC 225. In some embodiments, a network such as 5GCN 240 mayadditionally or alternatively implement other types of location-supportmodules, such as an Evolved Serving Mobile Location Center (E-SMLC) or aSUPL Location Platform (SLP). It is noted that in some embodiments, atleast part of the positioning functionality (including determination ofa UE 105′s location) may be performed at the UE 105 (e.g., by measuringdownlink PRS (DL-PRS) signals transmitted by wireless nodes such as gNBs210, ng-eNB 214 and/or WLAN 216, and/or using assistance data providedto the UE 105, e.g., by LMF 220).

The Gateway Mobile Location Center (GMLC) 225 may support a locationrequest for the UE 105 received from an external client 230 and mayforward such a location request to the AMF 215 for forwarding by the AMF215 to the LMF 220. A location response from the LMF 220 (e.g.,containing a location estimate for the UE 105) may be similarly returnedto the GMLC 225 either directly or via the AMF 215, and the GMLC 225 maythen return the location response (e.g., containing the locationestimate) to the external client 230.

A Network Exposure Function (NEF) 245 may be included in 5GCN 240. TheNEF 245 may support secure exposure of capabilities and eventsconcerning 5GCN 240 and UE 105 to the external client 230, which maythen be referred to as an Access Function (AF) and may enable secureprovision of information from external client 230 to 5GCN 240. NEF 245may be connected to AMF 215 and/or to GMLC 225 for the purposes ofobtaining a location (e.g., a civic location) of UE 105 and providingthe location to external client 230.

As further illustrated in FIG. 2 , the LMF 220 may communicate with thegNBs 210 and/or with the ng-eNB 214 using an NR Positioning Protocolannex (NRPPa) as defined in 3GPP Technical Specification (TS) 38.455.NRPPa messages may be transferred between a gNB 210 and the LMF 220,and/or between an ng-eNB 214 and the LMF 220, via the AMF 215. Asfurther illustrated in FIG. 2 , LMF 220 and UE 105 may communicate usingan LTE Positioning Protocol (LPP) as defined in 3GPP TS 37.355. Here,LPP messages may be transferred between the UE 105 and the LMF 220 viathe AMF 215 and a serving gNB 210-1 or serving ng-eNB 214 for UE 105.For example, LPP messages may be transferred between the LMF 220 and theAMF 215 using messages for service-based operations (e.g., based on theHypertext Transfer Protocol (HTTP)) and may be transferred between theAMF 215 and the UE 105 using a 5G NAS protocol. The LPP protocol may beused to support positioning of UE 105 using UE assisted and/or UE basedposition methods such as A-GNSS, RTK, TDOA, multi-cell RTT, AoD, and/orECID. The NRPPa protocol may be used to support positioning of UE 105using network-based position methods such as ECID, AoA, uplink TDOA(UL-TDOA) and/or may be used by LMF 220 to obtain location relatedinformation from gNBs 210 and/or ng-eNB 214, such as parameters definingDL-PRS transmission from gNBs 210 and/or ng-eNB 214.

In the case of UE 105 access to WLAN 216, LMF 220 may use NRPPa and/orLPP to obtain a location of UE 105 in a similar manner to that justdescribed for UE 105 access to a gNB 210 or ng-eNB 214. Thus, NRPPamessages may be transferred between a WLAN 216 and the LMF 220, via theAMF 215 and N3IWF 250 to support network-based positioning of UE 105and/or transfer of other location information from WLAN 216 to LMF 220.Alternatively, NRPPa messages may be transferred between N3IWF 250 andthe LMF 220, via the AMF 215, to support network-based positioning of UE105 based on location related information and/or location measurementsknown to or accessible to N3IWF 250 and transferred from N3IWF 250 toLMF 220 using NRPPa. Similarly, LPP and/or LPP messages may betransferred between the UE 105 and the LMF 220 via the AMF 215, N3IWF250, and serving WLAN 216 for UE 105 to support UE assisted or UE basedpositioning of UE 105 by LMF 220.

In a 5G NR positioning system 200, positioning methods can becategorized as being “UE assisted” or “UE based.” This may depend onwhere the request for determining the position of the UE 105 originated.If, for example, the request originated at the UE (e.g., from anapplication, or “app,” executed by the UE), the positioning method maybe categorized as being UE based. If, on the other hand, the requestoriginates from an external client or AF 230, LMF 220, or other deviceor service within the 5G network, the positioning method may becategorized as being UE assisted (or “network-based”).

With a UE-assisted position method, UE 105 may obtain locationmeasurements and send the measurements to a location server (e.g., LMF220) for computation of a location estimate for UE 105. ForRAT-dependent position methods location measurements may include one ormore of a Received Signal Strength Indicator (RSSI), Round Trip signalpropagation Time (RTT), Reference Signal Received Power (RSRP),Reference Signal Received Quality (RSRQ), Reference Signal TimeDifference (RSTD), Time of Arrival (TOA), AoA, Receive Time-TransmissionTime Difference (Rx-Tx), Differential AoA (DAoA), AoD, or Timing Advance(TA) for gNBs 210, ng-eNB 214, and/or one or more access points for WLAN216. Additionally or alternatively, similar measurements may be made ofsidelink signals transmitted by other UEs, which may serve as anchorpoints for positioning of the UE 105 if the positions of the other UEsare known. The location measurements may also or instead includemeasurements for RAT-independent positioning methods such as GNSS (e.g.,GNSS pseudorange, GNSS code phase, and/or GNSS carrier phase for GNSSsatellites 110), WLAN, etc.

With a UE-based position method, UE 105 may obtain location measurements(e.g., which may be the same as or similar to location measurements fora UE assisted position method) and may further compute a location of UE105 (e.g., with the help of assistance data received from a locationserver such as LMF 220, an SLP, or broadcast by gNBs 210, ng-eNB 214, orWLAN 216).

With a network based position method, one or more base stations (e.g.,gNBs 210 and/or ng-eNB 214), one or more APs (e.g., in WLAN 216), orN3IWF 250 may obtain location measurements (e.g., measurements of RSSI,RTT, RSRP, RSRQ, AoA, or TOA) for signals transmitted by UE 105, and/ormay receive measurements obtained by UE 105 or by an AP in WLAN 216 inthe case of N3IWF 250, and may send the measurements to a locationserver (e.g., LMF 220) for computation of a location estimate for UE105.

Positioning of the UE 105 also may be categorized as UL, DL, or DL-ULbased, depending on the types of signals used for positioning. If, forexample, positioning is based solely on signals received at the UE 105(e.g., from a base station or other UE), the positioning may becategorized as DL based. On the other hand, if positioning is basedsolely on signals transmitted by the UE 105 (which may be received by abase station or other UE, for example), the positioning may becategorized as UL based. Positioning that is DL-UL based includespositioning, such as RTT-based positioning, that is based on signalsthat are both transmitted and received by the UE 105. Sidelink(SL)-assisted positioning comprises signals communicated between the UE105 and one or more other UEs. According to some embodiments, UL, DL, orDL-UL positioning as described herein may be capable of using SLsignaling as a complement or replacement of SL, DL, or DL-UL signaling.

Depending on the type of positioning (e.g., UL, DL, or DL-UL based) thetypes of reference signals used can vary. For DL-based positioning, forexample, these signals may comprise PRS (e.g., DL-PRS transmitted bybase stations or SL-PRS transmitted by other UEs), which can be used forTDOA, AoD, and RTT measurements. Other reference signals that can beused for positioning (UL, DL, or DL-UL) may include Sounding ReferenceSignal (SRS), Channel State Information Reference Signal (CSI-RS),synchronization signals (e.g., synchronization signal block (SSB)Synchronizations Signal (SS)), Physical Uplink Control Channel (PUCCH),Physical Uplink Shared Channel (PUSCH), Physical Sidelink Shared Channel(PSSCH), Demodulation Reference Signal (DMRS), etc. Moreover, referencesignals may be transmitted in a Tx beam and/or received in an Rx beam(e.g., using beamforming techniques), which may impact angularmeasurements, such as AoD and/or AoA.

As previously noted, the estimated location of a target UE (e.g., UE105) may be based on measurements of RF signals sent from and/orreceived by the target UE (e.g., DL-UL based and/or DL-basedpositioning). For example, when performing RTT based positioning, theRTT may be determined based on a total delay of the signal transmittedbetween base stations (e.g., gNBs 210 and/or ng-eNB 214) and the targetUE. For example, the total delay may be determined based on performing across-correlation between the signal transmitted from a base station andthe signal received by the target UE. The peak of the cross-correlationmay be used to determine the total delay. Specifically, FIG. 3illustrates an example sampled cross-correlation R[m] between a sampledsignal x(k) sampled based on a signal x(t) (e.g., t=kT, where thesampling rate Fs=1/T ) which is transmitted by a base station and asampled signal y(k) sampled based on a signal y(t) (e.g., t=kT, wherethe sampling rate Fs=1/T ) which is received by the target UE.

As illustrated in FIG. 3 , at time point t0, an analog signal x(t) istransmitted from the base station (e.g., a gNB). At time point t1, theanalog signal y(t) is received by the target UE. In some embodiments,the received signal y(t) can be determined according to equation (1):

$\begin{matrix}{y(t) = Ge^{j\varphi}x\left( {t - \Delta\tau} \right) + \text{n}\left( \text{t} \right)} & \text{­­­(1)}\end{matrix}$

where G denotes the gain (e.g., adjusted by a gain control module), φdenotes the phase shift, Δ_(T) denotes the total delay between x(t) andy(t) (e.g., Δ_(T)=t1-t0), and n(t) denotes the noise introduced duringthe process. Upon receipt, the target UE preprocesses the analog signal(e.g., sampling, filtering, and/or adjusting gains) and the receivedsignal y(t) is converted to a digital signal (e.g., a discrete signal)y[k] at a sampling rate of Fs (e.g., y[k] = y(t = kT), where thesampling rate Fs=1/T) by an ADC. By determining a sampledcross-correlation R[m] between the sampled signal y[k] and the sampledreference signal x[k] sampled based on x[t] at the sampling frequency ofFs (e.g., x[k] = x(t = kT), R[m] = < y[k + m], x[k] >), the total delayΔ_(T) can be determined accordingly.

For example, as illustrated in FIG. 3 , the m₁th (e.g., start countingfrom t0) sample of R[m] may correspond to the peak in the plot of R[m]and m₁T may be interpreted as the total delay Δ_(T) between x(t) andy(t) (e.g., m₁T ≈ Δ_(T)) accordingly. It is understood that because bothx[k] and y[k] are discrete signals (e.g., sampled at a the sampling rateFs), the peak of the plot of R [t] (e.g., the cross-correlation betweenx(t) and y(t), R[t] =< y[t + Δ_(T]), x[t] >) may not necessarilycoincide at an integer sample offset in R[m], namely, m₁T may notexactly equal to Δτ (e.g., offset by a difference between the two dashedvertical lines t′).

As previously noted, an accurate calculation of the measurementsdetermined based on the RF signal, may be based on a precise knowledgeof the ADC output timing (e.g., the timing of the sets of ADC samples).Existing ADC sampling systems have uncertainties in determining the ADCoutput timing due to accumulated delay in the long ADC output clockgeneration path. For example, FIG. 4A is a diagram illustrating anexisting ADC sampling system 400. As illustrated in FIG. 4A, in someembodiments, ADC sampling system 400 includes an oscillator (XO) 402configured to generate a system clock (e.g., a reference clock at 38.4MHz), an ADC input clock generation module 410 configured to generate anADC input clock based on the system clock, a RF circuits 420, and an ADC430 configured to convert the received analog signals (e.g., receivedfrom an input terminal of ADC 430) to digital signals (e.g., sampling).In some embodiments, RF circuits 420 may include a transceiverconfigured to receive the analog signals.

In some embodiments, ADC input clock generation module 410 may generatethe ADC input clock by adjusting the rate of the system clock.Specifically, ADC input clock generation module 410 may include aphase-locked loop (PLL) 412 configured to multiply the rate of thesystem clock by a first predetermined value (e.g., generate an outputfrequency at multiples of an input frequency), a clock divider 414configured to divide the rate of the multiplied system clock by a secondpredetermined value (e.g., generate an output frequency at fractions ofan input frequency), and a low voltage differential signaling (LVDS) 416configured to route the adjusted system clock to ADC 430. For example,the first value may be set as 3 (e.g., multiply the rate of the systemclock by 3), and the second value may be set as 2 (e.g., divided therate of the multiplied system clock by 2). The generated ADC input clockmay be input to ADC 430 (e.g., input to a clock terminal of ADC 430)along with the analog signal received from RF circuits (e.g., input frominput terminal of ADC 430). ADC 430 may output a set of ADC samplesgenerated based on sampling the signal input from the input terminal(e.g., the analog signal received by the transceiver) according to theADC input clock and may output an ADC output clock accordingly. The ADCoutput clock may include certain delays to the ADC input clock due tothe circuitry of ADC 430.

In some embodiments, ADC sampling system 400 may further include a modem440 (e.g., a processor) configured to manage ADC sampling system 400.For example, modem 440 may be configured to generate a start signalindicating a starting point of capturing the set of ADC samplesgenerated by ADC 430. ADC sampling system 400 may also include a counter450. Specifically, modem 440 may start ADC 430 at a pre-determined timepoint, which is set by pre-programming a value. At the pre-determinedtime point, counter 450 will trigger and provide to the ADC an “enable”signal, synchronized to the system clock from XO 402, for starting ADC430. In some embodiments, ADC sampling system 400 may also include afirst in first out (FIFO) memory/buffer (not shown) configured tostore/capture the set of ADC samples based on the capturing sampleclock. For example, ADC sampling system 400 may further include an ANDgate (not shown) configured to combine the ADC output clock with theresynchronized start signal to generate the capturing sample clock forthe FIFO memory/buffer to store/capture the set of ADC samples.

Because of the long generation chain for generating the ADC outputclock, the timing and/or delay of the output of ADC 430 (e.g., the setof ADC samples) is uncertain. Specifically, the delay in clock signalscaused by the circuits (e.g., PLL 412, clock divider 414, and LVDS 416in ADC input clock generation module 410, and ADC 430) varies with thetemperature and the process corner of the circuits. For example, FIG. 4Billustrates timing diagrams for each of the clock signals in ADCsampling system 400 in different situations. Specifically, FIG. 4B showsthe examples of delays in both a high temperature situation, situation 1(e.g., START 1, ADC OUT 1, and Sample capture 1), and a low temperaturesituation, situation 2 (e.g., START 2, ADC OUT 2, and Sample capture 2).As illustrated in FIG. 4B, XO 402 may generate the system clock at apredetermined rate (e.g., at 38.4 MHz) and the system clock may be usedas a reference clock. When it is decided (e.g., by modem 440) in orderto perform an RTT or similar measurement, to capture samples in the setof ADC samples (e.g., store the samples in the FIFO memory/buffer), aregister of modem 440 may generate start signals (e.g., START 1 and/orSTART 2) indicating a starting point of the FIFO memory/buffer capturingthe set of ADC samples. The initiation of the start signal is programmedto happen at a pre-determined time point by setting the value at whichthe counter will trigger it. For example, the pre-determined time pointmay be set by pre-programming a value at which counter 450 will triggerand provide to the ADC an “enable” signal, synchronized to the systemclock from XO 402, for starting ADC 430. After processing by ADC inputclock generation module 410 (e.g., by the PLL, the clock divider, andthe LVDS) and ADC 430, the ADC output clock (e.g., ADC OUT 1 and ADC OUT2) may have uncertain delay in timing with respect to the system clock.

For example, as illustrated in FIG. 4B, because of the temperature andprocess corner differences in situations 1 and 2, the rising edge of ADCOUT 1 in situation 1 is slightly (e.g., less than a cycle) behind therising edge of the system clock (e.g., with a slow/hot process corner)and the rising edge of ADC OUT 2 in situation 2 is slightly (e.g., lessthan a cycle) ahead of the rising edge of the system clock (e.g., with afast/cold process corner). Because the sample capture clock (e.g.,Sample capture 1 and Sample capture 2) is generated along a pathcontaining uncertain variations (e.g., delays caused by the processingcircuits such as PLL 412, clock divider 414, LVDS 416, and ADC 430), theADC output clock may have up to a 2-cycle timing difference in thesample capture clocks (e.g., Sample capture 1 and Sample capture 2) forthe FIFO memory/buffer to capture/store the corresponding set of outputsamples of ADC 430.

It is contemplated that some of the components in ADC sampling system400 described herein may be optional and ADC sampling system 400 mayalso include other suitable hardware and/or software components withoutdeviate from the spirit of the technology. For ease of illustration, thetechnical details of the components disclosed herein will not be furtherdescribed and will not affect the functioning of the technologydisclosed herein. A person skilled in the art to which the disclosurepertains can figure out how those components work without undueexperiments.

FIG. 5 is a diagram illustrating an example ADC sampling system 500according to an embodiment. ADC sampling system 500 is similar to ADCsampling system 400, except ADC sampling system 500 includes a switch510 in addition to the components in ADC sampling system 400, configuredto control the working mode of ADC sampling system 500. FIG. 6illustrates a flowchart of an exemplary method 600 for determining ADCoutput timing in ADC sampling system 500, according to an embodiment.Means for performing the functionality illustrated in one or more of theblocks shown in FIG. 6 may be performed by hardware and/or softwarecomponents of a target UE including ADC sampling system 500. Examplecomponents of the target UE are illustrated in FIG. 5 . It is to beappreciated that some of the functionalities illustrated in one or moreof the blocks shown in FIG. 6 may be optional to perform the disclosureprovided herein. Further, some of the functionalities illustrated in oneor more of the blocks shown in FIG. 6 may be performed simultaneously,or in a different order than shown in FIG. 6 . FIG. 5 and FIG. 6 will bedescribed together.

As shown in FIG. 5 , switch 510 may operate in a first mode (e.g.,connecting to position 1) or a second mode (e.g., connecting to position2). In some embodiments, the operation of switch 510 may be controlledby a processor (e.g., modem 440). For example, modem 440 may determinethe operation mode (e.g., the first mode or the second mode) of switch510. When working in the first mode, the system clock generated byoscillator 402 may be directly routed to the input terminal of ADC 430for sampling. Accordingly, ADC sampling system 500 may correspondinglywork in an ADC output timing determination mode. When working in thesecond mode, the analog signals received from RF circuits 420 (e.g.,received by the transceiver of RF circuits 420) may be directly routedto the input terminal of ADC 430 for sampling. Accordingly, ADC samplingsystem 500 may correspondingly work in a regular working mode (e.g.,processing the signal received and/or transmitted).

For example, at block 610, the functionality comprises operating switch510 in the first mode (e.g., switch 510 switches to position 1) to routethe system clock from oscillator 402 to the input terminal of ADC 430.Means for performing functionality at block 610 may comprise modem 440,and/or other components of the target UE (e.g., UE 105), as illustratedin FIG. 9 . ADC 430 may sample the system clock based on the input ADCclock generated by ADC input clock generation module 410 to generate afirst set of ADC samples. Accordingly, the first set of ADC samples mayinclude information regarding both the system clock and the ADC inputclock. Specifically, ADC input clock generation module 410 may includePLL 412 configured to multiply the rate of the system clock by a firstpredetermined value (e.g., generate an output frequency at multiples ofan input frequency), clock divider 414 configured to divide the rate ofthe multiplied system clock by a second predetermined value (e.g.,generate an output frequency at fractions of an input frequency), andLVDS 416 configured to route the adjusted system clock to ADC 430. Forexample, the first value may be set as 3 (e.g., multiply the rate of thesystem clock by 3), and the second value may be set as 2 (e.g., dividedthe rate of the multiplied system clock by 2). The generated ADC inputclock may be input to ADC 430 (e.g., input to a clock terminal of ADC430) along with the system clock (e.g., input at the input terminal ofADC 430). The system clock may be sampled based on the ADC input clockto generate the first set of ADC samples accordingly.

At block 620, the functionality comprises determining a first ADC outputtiming based on the first set of ADC samples generated by ADC 430. Meansfor performing functionality at block 620 may comprise modem 440 and/orother components of the target UE (e.g., UE 105), as illustrated in FIG.9 . For example, modem 440 may scan for rising edges of the system clockin the first set of ADC samples. Accordingly, output timing of ADC 430(e.g., the exact timing of the ADC samples can be determined) may bedetermined.

At block 630, the functionality comprises operating switch 510 in asecond mode (e.g., switch 510 switches to position 2) to route analogsignals received from RF circuit 420 (e.g., received by a transceiver)to the input terminal of ADC 430. Means for performing functionality atblock 630 may comprise modem 440 and/or other components of the targetUE (e.g., UE 105), as illustrated in FIG. 9 .

At block 640, the functionality comprises sampling the analog signalsreceived from RF circuit 420 based on the input ADC clock generated byADC input clock generation module 410 to generate/obtain a second set ofADC output samples. Means for performing functionality at block 640 maycomprise ADC 430 and/or other components of the target UE (e.g., UE105), as illustrated in FIG. 9 .

At block 650, the functionality comprises determining the output timingof the second set of ADC samples based at least in part on thedetermined first ADC output timing. Means for performing functionalityat block 650 may comprise modem 440 and/or other components of thetarget UE (e.g., UE 105), as illustrated in FIG. 9 . For example,because both the first set of ADC samples and the second set of ADCsamples are sampled at the same sampling rate (e.g., according to theADC input clock), the output timing of the second set of ADC samples maybe determined as the same as the determined first ADC output timing(e.g., the output timing of the first set of ADC samples).

Because the system clock is directly routed to the input terminal of ADC430 when generating the first set of ADC samples, the output timing ofthe first set of ADC samples determined based on using the system clockas the reference can be obtained with no uncertainty. Accordingly, theoutput timing of ADC 430 when functioning in the regular working mode(e.g., the output timing of the second set of ADC samples generatedbased on the analog signal received from the transceiver when switch 510is in position 2) can be determined accurately based on the outputtiming of the first set of ADC samples.

FIG. 7A is a diagram illustrating another example ADC sampling system700 and FIG. 7B illustrates timing diagrams for clock signals in ADCsampling system 700 according to an embodiment. ADC sampling system 700is similar to ADC sampling system 400, except ADC sampling system 700includes an ADC output timing determination module 710 in addition tothe components in ADC sampling system 400, configured to determine theADC output timing in ADC sampling system 700. FIG. 8 illustrates aflowchart of an exemplary method 800 for determining ADC output timingin ADC sampling system 700, according to an embodiment. Means forperforming the functionality illustrated in one or more of the blocksshown in FIG. 8 may be performed by hardware and/or software componentsof a target UE including ADC sampling system 700. Example components ofthe target UE are illustrated in FIG. 7A. It is to be appreciated thatsome of the functionalities illustrated in one or more of the blocksshown in FIG. 8 may be optional to perform the disclosure providedherein. Further, some of the functionalities illustrated in one or moreof the blocks shown in FIG. 8 may be performed simultaneously, or in adifferent order than shown in FIG. 8 . FIGS. 7A and 7B, and FIG. 8 willbe described together.

As shown in FIG. 7A, ADC sampling system 700 may include an ADC outputtiming determination module 710 configured to obtain an ADC outputtiming, a clock domain crossing (CDC) 760 configured to resynchronizethe synchronized start signal with the ADC output clock, an AND gate 770configured to generate a capturing sample clock for capturing the set ofADC samples generated by ADC 430, and a first in first out (FIFO)memory/buffer 780 configured to store/capture the set of ADC samplesbased on the capturing sample clock. For example, AND gate 770 maycombine the ADC output clock with the resynchronized start signal togenerate the capturing sample clock for FIFO memory/buffer 780 tostore/capture the set of ADC samples.

In some embodiments, ADC output timing determination module 710 mayinclude a phase lock loop (PLL) 712 and a counter 714. PLL 712 may beconfigured to generate a high frequency clock (e.g., the PLL outputclock may be used as a counter clock for counter 714) based on thesystem clock (e.g., multiply the rate of the system clock by a thirdvalue, such as 5, 10, 15, 20, etc.). Counter 714 may be configured tocalculate the ADC output timing based on the high frequency clock. Insome embodiments, counter 714 may include a first input terminal (aSTART terminal) and a second input terminal (e.g., a STOP terminal)configured to receive the start signal synchronized by counter 450(e.g., synchronize the start signal with the system clock with apredetermined time-delay) and the capturing sample clock (e.g.,generated by AND gate 770) respectively. Counter 714 may count the timedifference between receiving the synchronized start signal (e.g.,indicating the time point for capturing ADC samples determined/intendedby modem 440, shown as time point B in FIG. 7B) and receiving thecapturing sample clock (e.g., the time point when ADC samples areactually captured, shown as time point C in FIG. 7B). In someembodiments, PLL 712 may be controlled by receiving a control signal 713(e.g., an Enable signal) from modem firmware/software (e.g., from modem440). For example, PLL 712 may be controlled (e.g., by modem 440) tostart generating the PLL output clock for counter 714 which may be usedas the counter clock at a time point few cycles before counter 714actually start to count the time difference between time point B andtime point C (e.g., start at time point A to generate the PLL outputclock). PLL 712 may also be controlled (e.g., by modem 440) to stopgenerating the PLL output clock (e.g., turned off) few cycles aftercounter 714 stopped counting the time difference between time point Band time point C (e.g., turned off at time point D shown in FIG. 7B). Atsome time point after counter 714 stopped counting the time differencebetween time point B and time point C (e.g., at time point E shown inFIG. 7B), readout 715 of counter 714 indicating the time difference maybe output to a modem software (e.g., modem 440) for calculating of theADC output timing. Accordingly, the ADC output timing (e.g., the timingof ADC samples) can be obtained accurately.

Specifically, at block 810, the functionality comprises obtaining a setof ADC samples generated by ADC 430 based on analog signals receivedfrom RF circuits and an ADC input clock. Means for performingfunctionality at block 810 may comprise ADC input clock generationmodule 410, RF circuits 420, and/or other components of the target UE(e.g., UE 105), as illustrated in FIG. 9 .

At block 820, the functionality comprises generating, at a first timepoint, a start signal indicating a starting point of capturing the setof ADC samples. Means for performing functionality at block 820 maycomprise modem 440 and/or other components of the target UE (e.g., UE105), as illustrated in FIG. 9 .

At block 830, the functionality comprises synchronizing, at a secondtime point (e.g., at time point B shown in FIG. 7B), the start signaland a system clock. Means for performing functionality at block 820 maycomprise modem 440, counter 450 and/or other components of the target UE(e.g., UE 105), as illustrated in FIG. 9 .

At block 840, the functionality comprises generating, at a third timepoint (e.g., at time point C shown in FIG. 7B), a capturing sample clockfor capturing the set of ADC sample. Means for performing functionalityat block 840 may comprise modem 440 and/or other components of thetarget UE (e.g., UE 105), as illustrated in FIG. 9 . The capturingsample clock indicates the actual start time of ADC sample capturing.The process for the generation of the capturing sample clock is similarto the capturing sample clock generation in ADC sampling systems 400 and500, and for ease of illustration, the process will not be repeated.

At block 850, the functionality comprises inputting the synchronizedstart signal and the capturing sample clock to counter 714 to determinea time difference between the second time point and the third timepoint. Means for performing functionality at block 850 may comprise ADC430 and/or other components of the target UE (e.g., UE 105), asillustrated in FIG. 9 . The synchronized start signal and the capturingsample clock may be fed to a start terminal and a stop terminal totrigger the start of counting and the stop of counting in counter 714respectively. Specifically, counter 714 starts to count when thesynchronized start signal is fed to the first input terminal of counter714 at time point B as shown in FIG. 7B. The synchronized start signalindicates the intended start time of ADC sample capturing by the FIFOmemory/buffer. Counter 714 stops to count when the capturing sampleclock is fed to the second input terminal of counter 714 at time point Cas shown in FIG. 7B. The capturing sample clock indicates the actualstart time of ADC sample capturing by the FIFO memory/buffer.

At block 860, the functionality comprises determining the ADC outputtiming of the set of ADC samples based on the time difference. Means forperforming functionality at block 860 may comprise modem 440 and/orother components of the target UE (e.g., UE 105), as illustrated in FIG.9 . Specifically, the time difference between the intended ADC samplecapture time and the actual ADC sample capture time can be used fordetermining the ADC output timing (e.g., the delay) of the set of ADCsamples.

Because the synchronized start signal includes the information of thesystem clock (e.g., is synchronized with the system clock), and isdirectly routed to the input terminal of the PLL 712 along with thecapturing sample clock for determining the output timing of ADC 430, theoutput timing of ADC 430 can be determined preciously as a result. Forexample, modem 440 and/or other components of the target UE (e.g., UE105), as illustrated in FIG. 9 may receive the output of counter 714(e.g., the readout) and determine the output timing of ADC 430accordingly.

FIG. 9 is a block diagram of an embodiment of a UE 105, which can beutilized as described herein above (e.g., in association with FIGS. 4A,5, and 7A). For example, the UE 105 can perform one or more of thefunctions of the method shown in FIGS. 6 and 8 . It should be noted thatFIG. 9 is meant only to provide a generalized illustration of variouscomponents, any or all of which may be utilized as appropriate. It canbe noted that, in some instances, components illustrated by FIG. 9 canbe localized to a single physical device and/or distributed amongvarious networked devices, which may be disposed at different physicallocations. Furthermore, as previously noted, the functionality of the UEdiscussed in the previously described embodiments may be executed by oneor more of the hardware and/or software components illustrated in FIG. 9.

The UE 105 is shown comprising hardware elements that can beelectrically coupled via a bus 905 (or may otherwise be incommunication, as appropriate). The hardware elements may include aprocessor(s) 910 which can include without limitation one or moregeneral-purpose processors (e.g., an application processor), one or morespecial-purpose processors (such as digital signal processor (DSP)chips, graphics acceleration processors, application specific integratedcircuits (ASICs), and/or the like), and/or other processing structuresor means. Processor(s) 910 may comprise one or more processing units,which may be housed in a single integrated circuit (IC) or multiple ICs.As shown in FIG. 9 , some embodiments may have a separate DSP 920,depending on desired functionality. Location determination and/or otherdeterminations based on wireless communication may be provided in theprocessor(s) 910 and/or wireless communication interface 930 (discussedbelow). The UE 105 also can include one or more input devices 970, whichcan include without limitation one or more keyboards, touch screens,touch pads, microphones, buttons, dials, switches, and/or the like; andone or more output devices 915, which can include without limitation oneor more displays (e.g., touch screens), light emitting diodes (LEDs),speakers, and/or the like.

The UE 105, modem 440, and other circuitry in FIGS. 4A, 5, and 7A mayalso include a wireless communication interface 930, which may comprisewithout limitation a modem, a network card, an infrared communicationdevice, a wireless communication device, and/or a chipset (such as aBluetooth® device, an IEEE 802.11 device, an IEEE 802.15.4 device, aWi-Fi device, a WiMAX device, a WAN device, and/or various cellulardevices, etc.), and/or the like, which may enable the UE 105 tocommunicate with other devices as described in the embodiments above.The wireless communication interface 930 may permit data and signalingto be communicated (e.g., transmitted and received) with TRPs of anetwork, for example, via eNBs, gNBs, ng-eNBs, access points, variousbase stations and/or other access node types, and/or other networkcomponents, computer systems, and/or any other electronic devicescommunicatively coupled with TRPs, as described herein. Thecommunication can be carried out via one or more wireless communicationantenna(s) 932 that send and/or receive wireless signals 934. Accordingto some embodiments, the wireless communication antenna(s) 932 maycomprise a plurality of discrete antennas, antenna arrays, or anycombination thereof. The antenna(s) 932 may be capable of transmittingand receiving wireless signals using beams (e.g., Tx beams and Rxbeams). Beam formation may be performed using digital and/or analog beamformation techniques, with respective digital and/or analog circuitry.The wireless communication interface 930 may include such circuitry.

Depending on desired functionality, the wireless communication interface930 may comprise a separate receiver and transmitter, or any combinationof transceivers, transmitters, and/or receivers to communicate with basestations (e.g., ng-eNBs and gNBs) and other terrestrial transceivers,such as wireless devices and access points. The UE 105 may communicatewith different data networks that may comprise various network types.For example, a Wireless Wide Area Network (WWAN) may be a CDMA network,a Time Division Multiple Access (TDMA) network, a Frequency DivisionMultiple Access (FDMA) network, an Orthogonal Frequency DivisionMultiple Access (OFDMA) network, a Single-Carrier Frequency DivisionMultiple Access (SC-FDMA) network, a WiMAX (IEEE 802.16) network, and soon. A CDMA network may implement one or more RATs such as CDMA2000®,WCDMA, and so on. CDMA2000® includes IS-95, IS-2000 and/or IS-856standards. A TDMA network may implement GSM, Digital Advanced MobilePhone System (D-AMPS), or some other RAT. An OFDMA network may employLTE, LTE Advanced, 5G NR, and so on. 5G NR, LTE, LTE Advanced, GSM, andWCDMA are described in documents from 3GPP. CDMA2000® is described indocuments from a consortium named “3rd Generation Partnership Project 2”(3GPP2). 3GPP and 3GPP2 documents are publicly available. A wirelesslocal area network (WLAN) may also be an IEEE 802.11x network, and awireless personal area network (WPAN) may be a Bluetooth network, anIEEE 802.15x, or some other type of network. The techniques describedherein may also be used for any combination of WWAN, WLAN and/or WPAN.

The UE 105 can further include sensor(s) 940. Sensor(s) 940 maycomprise, without limitation, one or more inertial sensors and/or othersensors (e.g., accelerometer(s), gyroscope(s), camera(s),magnetometer(s), altimeter(s), microphone(s), proximity sensor(s), lightsensor(s), barometer(s), and the like), some of which may be used toobtain position-related measurements and/or other information.

Embodiments of the UE 105 may also include a Global Navigation SatelliteSystem (GNSS) receiver 980 capable of receiving signals 984 from one ormore GNSS satellites using an antenna 982 (which could be the same asantenna 932). Positioning based on GNSS signal measurement can beutilized to complement and/or incorporate the techniques describedherein. The GNSS receiver 980 can extract a position of the UE 105,using conventional techniques, from GNSS satellites 110 of a GNSSsystem, such as Global Positioning System (GPS), Galileo, GLONASS,Quasi-Zenith Satellite System (QZSS) over Japan, IRNSS over India,BeiDou Navigation Satellite System (BDS) over China, and/or the like.Moreover, the GNSS receiver 980 can be used with various augmentationsystems (e.g., a Satellite Based Augmentation System (SBAS)) that may beassociated with or otherwise enabled for use with one or more globaland/or regional navigation satellite systems, such as, e.g., Wide AreaAugmentation System (WAAS), European Geostationary Navigation OverlayService (EGNOS), Multi-functional Satellite Augmentation System (MSAS),and Geo Augmented Navigation system (GAGAN), and/or the like.

It can be noted that, although GNSS receiver 980 is illustrated in FIG.9 as a distinct component, embodiments are not so limited. As usedherein, the term “GNSS receiver” may comprise hardware and/or softwarecomponents configured to obtain GNSS measurements (measurements fromGNSS satellites). In some embodiments, therefore, the GNSS receiver maycomprise a measurement engine executed (as software) by one or moreprocessors, such as processor(s) 910, DSP 920, and/or a processor withinthe wireless communication interface 930 (e.g., in a modem). A GNSSreceiver may optionally also include a positioning engine, which can useGNSS measurements from the measurement engine to determine a position ofthe GNSS receiver using an Extended Kalman Filter (EKF), Weighted LeastSquares (WLS), a hatch filter, particle filter, or the like. Thepositioning engine may also be executed by one or more processors, suchas processor(s) 910 or DSP 920.

The UE 105 may further include and/or be in communication with a memory960. The memory 960 can include, without limitation, local and/ornetwork accessible storage, a disk drive, a drive array, an opticalstorage device, a solid-state storage device, such as a random accessmemory (RAM), and/or a read-only memory (ROM), which can beprogrammable, flash-updateable, and/or the like. Such storage devicesmay be configured to implement any appropriate data stores, includingwithout limitation, various file systems, database structures, and/orthe like.

The memory 960 of the UE 105 also can comprise software elements (notshown in FIG. 9 ), including an operating system, device drivers,executable libraries, and/or other code, such as one or more applicationprograms, which may comprise computer programs provided by variousembodiments, and/or may be designed to implement methods, and/orconfigure systems, provided by other embodiments, as described herein.Merely by way of example, one or more procedures described with respectto the method(s) discussed above may be implemented as code and/orinstructions in memory 960 that are executable by the UE 105 (and/orprocessor(s) 910 or DSP 920 within UE 105). In some embodiments, then,such code and/or instructions can be used to configure and/or adapt ageneral-purpose computer (or other device) to perform one or moreoperations in accordance with the described methods.

It will be apparent to those skilled in the art that substantialvariations may be made in accordance with specific requirements. Forexample, customized hardware might also be used and/or particularelements might be implemented in hardware, software (including portablesoftware, such as applets, etc.), or both. Further, connection to othercomputing devices such as network input/output devices may be employed.

With reference to the appended figures, components that can includememory can include non-transitory machine-readable media. The term“machine-readable medium” and “computer-readable medium” as used herein,refer to any storage medium that participates in providing data thatcauses a machine to operate in a specific fashion. In embodimentsprovided hereinabove, various machine-readable media might be involvedin providing instructions/code to processors and/or other device(s) forexecution. Additionally or alternatively, the machine-readable mediamight be used to store and/or carry such instructions/code. In manyimplementations, a computer-readable medium is a physical and/ortangible storage medium. Such a medium may take many forms, includingbut not limited to, non-volatile media and volatile media. Common formsof computer-readable media include, for example, magnetic and/or opticalmedia, any other physical medium with patterns of holes, a RAM, aprogrammable ROM (PROM), erasable PROM (EPROM), a FLASH-EPROM, any othermemory chip or cartridge, or any other medium from which a computer canread instructions and/or code.

The methods, systems, and devices discussed herein are examples. Variousembodiments may omit, substitute, or add various procedures orcomponents as appropriate. For instance, features described with respectto certain embodiments may be combined in various other embodiments.Different aspects and elements of the embodiments may be combined in asimilar manner. The various components of the figures provided hereincan be embodied in hardware and/or software. Also, technology evolvesand, thus many of the elements are examples that do not limit the scopeof the disclosure to those specific examples.

It has proven convenient at times, principally for reasons of commonusage, to refer to such signals as bits, information, values, elements,symbols, characters, variables, terms, numbers, numerals, or the like.It should be understood, however, that all of these or similar terms areto be associated with appropriate physical quantities and are merelyconvenient labels. Unless specifically stated otherwise, as is apparentfrom the discussion above, it is appreciated that throughout thisSpecification discussion utilizing terms such as “processing,”“computing,” “calculating,” “determining,” “ascertaining,”“identifying,” “associating,” “measuring,” “performing,” or the likerefer to actions or processes of a specific apparatus, such as a specialpurpose computer or a similar special purpose electronic computingdevice. In the context of this Specification, therefore, a specialpurpose computer or a similar special purpose electronic computingdevice is capable of manipulating or transforming signals, typicallyrepresented as physical electronic, electrical, or magnetic quantitieswithin memories, registers, or other information storage devices,transmission devices, or display devices of the special purpose computeror similar special purpose electronic computing device.

Terms, “and” and “or” as used herein, may include a variety of meaningsthat also is expected to depend, at least in part, upon the context inwhich such terms are used. Typically, “or” if used to associate a list,such as A, B, or C, is intended to mean A, B, and C, here used in theinclusive sense, as well as A, B, or C, here used in the exclusivesense. In addition, the term “one or more” as used herein may be used todescribe any feature, structure, or characteristic in the singular ormay be used to describe some combination of features, structures, orcharacteristics. However, it should be noted that this is merely anillustrative example and claimed subject matter is not limited to thisexample. Furthermore, the term “at least one of” if used to associate alist, such as A, B, or C, can be interpreted to mean any combination ofA, B, and/or C, such as A, AB, AA, AAB, AABBCCC, etc.

Having described several embodiments, various modifications, alternativeconstructions, and equivalents may be used without departing from thescope of the disclosure. For example, the above elements may merely be acomponent of a larger system, wherein other rules may take precedenceover or otherwise modify the application of the various embodiments.Also, a number of steps may be undertaken before, during, or after theabove elements are considered. Accordingly, the above description doesnot limit the scope of the disclosure.

In view of this description embodiments may include differentcombinations of features. Implementation examples are described in thefollowing numbered clauses:

Clause 1. A method for determining an analog-to-digital converter (ADC)output timing in a user equipment, comprising: operating a switch in afirst mode to route a system clock from an oscillator to an input of theADC; determining a first ADC output timing based on a first set of ADCsamples generated by the ADC; operating the switch in a second mode toroute analog signals from a transceiver of the user equipment to theinput of the ADC; and obtaining a second set of ADC samples generated bythe ADC based on the analog signals.

Clause 2. The method of clause 1 further comprises: determining anoutput timing of the second set of ADC samples based at least in part onthe determined first ADC output timing.

Clause 3. The method of claim 1 further comprises generating an ADCinput clock based on the system clock.

Clause 4. The method of claim 3, wherein generating the ADC input clockbased on the system clock further comprises: multiplying a rate of thesystem clock by a first predetermined value; and dividing the multipliedsystem clock rate by a second predetermined value.

Clause 5. The method of claim 4, wherein generating the ADC input clockbased on the system clock further comprises: routing the system clock tothe ADC based on low voltage differential signaling (LVDS).

Clause 6. The method of claim 1 further comprises generating a startsignal indicating a starting point of capturing the second set of ADCsamples.

Clause 7. The method of claim 6 further comprises generating the startsignal with a predetermined time-delay according to the system clock.

Clause 8. The method of claim 7 further comprises synchronizing thestart signal with an ADC output clock.

Clause 9. The method of claim 8 further comprises generating a capturingsample clock for capturing the second set of ADC samples, based oncombining the synchronized start signal and the ADC output clock usingan AND gate.

Clause 10. A device comprising: one or more transceivers configured toreceive analog signals; an analog-to-digital converter (ADC) configuredto generate ADC samples; a switch operatively connected to the one ormore transceivers and the ADC; and one or more processors configured to:operate the switch in a first mode to route a system clock from anoscillator to an input of the ADC; determine a first ADC output timingbased on a first set of ADC samples generated by the ADC; operate theswitch in a second mode to route analog signals from the one or moretransceivers of the user equipment to the input of the ADC; and obtain asecond set of ADC samples generated by the ADC based on the analogsignals.

Clause 11. The device of claim 10, wherein the one or more processors isfurther configured to: determine an output timing of the second set ofADC samples based at least in part on the determined first ADC outputtiming.

Clause 12. The device of claim 10, further comprises an ADC input clockgeneration module, configured to generate an ADC input clock based onthe system clock.

Clause 13. The device of claim 12, wherein the ADC input clockgeneration module is further configured to: multiply a rate of thesystem clock by a first predetermined value; and divide the multipliedsystem clock rate by a second predetermined value.

Clause 14. The device of claim 13, wherein the ADC input clockgeneration module is further configured to: route the system clock tothe ADC based on low voltage differential signaling (LVDS).

Clause 15. The device of claim 10, wherein the one or more processors isfurther configured to: generate a start signal indicating a startingpoint of capturing the second set of ADC samples.

Clause 16. The device of claim 15, further comprises a counter,configured to initiate the start signal with a predetermined time-delayaccording to the system clock.

Clause 17. The device of claim 16, further comprises a clock domaincrossing, configured to synchronize the start signal with an ADC outputclock.

Clause 18. The device of claim 16, further comprises an AND gateconfigured to generate a capturing sample clock for capturing the secondset of ADC samples, based on combining the synchronized start signal andthe ADC output clock.

Clause 19. A user equipment comprising: means for operating a switch ina first mode to route a system clock from an oscillator to an input ofthe ADC; means for determining a first ADC output timing based on afirst set of ADC samples generated by the ADC; means for operating theswitch in a second mode to route analog signals from a transceiver ofthe user equipment to the input of the ADC; and means for obtaining asecond set of ADC samples generated by the ADC based on the analogsignals.

Clause 20. The user equipment of claim 19 further comprises: means fordetermining an output timing of the second set of ADC samples based atleast in part on the determined first ADC output timing.

Clause 21. The user equipment of claim 19 further comprises means forgenerating an ADC input clock based on the system clock.

Clause 22. The user equipment of claim 21, wherein generating the ADCinput clock based on the system clock further comprises: means formultiplying a rate of the system clock by a first predetermined value;and means for dividing the multiplied system clock rate by a secondpredetermined value.

Clause 23. The user equipment of claim 22, wherein generating the ADCinput clock based on the system clock further comprises: means forrouting the system clock to the ADC based on low voltage differentialsignaling (LVDS).

Clause 24. The user equipment of claim 19 further comprises means forgenerating a start signal indicating a starting point of capturing thesecond set of ADC samples.

Clause 25. The user equipment of claim 24 further comprises means forgenerating the start signal with a predetermined time-delay according tothe system clock.

Clause 26. The user equipment of claim 25 further comprises means forsynchronizing the start signal with an ADC output clock.

Clause 27. The user equipment of claim 26 further comprises means forgenerating a capturing sample clock for capturing the second set of ADCsamples, based on combining the synchronized start signal and the ADCoutput clock using an AND gate.

What is claimed is:
 1. A method for determining an analog-to-digitalconverter (ADC) output timing in a user equipment, comprising: operatinga switch in a first mode to route a system clock from an oscillator toan input of the ADC; determining a first ADC output timing based on afirst set of ADC samples generated by the ADC; operating the switch in asecond mode to route analog signals from a transceiver of the userequipment to the input of the ADC; and obtaining a second set of ADCsamples generated by the ADC based on the analog signals.
 2. The methodof claim 1 further comprises: determining an output timing of the secondset of ADC samples based at least in part on the determined first ADCoutput timing.
 3. The method of claim 1 further comprises generating anADC input clock based on the system clock.
 4. The method of claim 3,wherein generating the ADC input clock based on the system clock furthercomprises: multiplying a rate of the system clock by a firstpredetermined value; and dividing the multiplied system clock rate by asecond predetermined value.
 5. The method of claim 4, wherein generatingthe ADC input clock based on the system clock further comprises: routingthe system clock to the ADC based on low voltage differential signaling(LVDS).
 6. The method of claim 1 further comprises generating a startsignal indicating a starting point of capturing the second set of ADCsamples.
 7. The method of claim 6 further comprises generating the startsignal with a predetermined time-delay according to the system clock. 8.The method of claim 7 further comprises synchronizing the start signalwith an ADC output clock.
 9. The method of claim 8 further comprisesgenerating a capturing sample clock for capturing the second set of ADCsamples, based on combining the synchronized start signal and the ADCoutput clock using an AND gate.
 10. A device comprising: one or moretransceivers configured to receive analog signals; an analog-to-digitalconverter (ADC) configured to generate ADC samples; a switch operativelyconnected to the one or more transceivers and the ADC; and one or moreprocessors configured to: operate the switch in a first mode to route asystem clock from an oscillator to an input of the ADC; determine afirst ADC output timing based on a first set of ADC samples generated bythe ADC; operate the switch in a second mode to route analog signalsfrom the one or more transceiver to the input of the ADC; and obtain asecond set of ADC samples generated by the ADC based on the analogsignals.
 11. The device of claim 10, wherein the one or more processorsis further configured to: determine an output timing of the second setof ADC samples based at least in part on the determined first ADC outputtiming.
 12. The device of claim 10, further comprises an ADC input clockgeneration module, configured to generate an ADC input clock based onthe system clock.
 13. The device of claim 12, wherein the ADC inputclock generation module is further configured to: multiply a rate of thesystem clock by a first predetermined value; and divide the multipliedsystem clock rate by a second predetermined value.
 14. The device ofclaim 13, wherein the ADC input clock generation module is furtherconfigured to: route the system clock to the ADC based on low voltagedifferential signaling (LVDS).
 15. The device of claim 10, wherein theone or more processors is further configured to: generate a start signalindicating a starting point of capturing the second set of ADC samples.16. The device of claim 15, further comprises a counter, configured toinitiate the start signal with a predetermined time-delay according tothe system clock.
 17. The device of claim 16, further comprises a clockdomain crossing, configured to synchronize the start signal with an ADCoutput clock.
 18. The device of claim 17, further comprises an AND gateconfigured to generate a capturing sample clock for capturing the secondset of ADC samples, based on combining the synchronized start signal andthe ADC output clock.
 19. A user equipment (UE) comprising: means foroperating a switch in a first mode to route a system clock from anoscillator to an input of the ADC; means for determining a first ADCoutput timing based on a first set of ADC samples generated by the ADC;means for operating the switch in a second mode to route analog signalsfrom a transceiver of the user equipment to the input of the ADC; andmeans for obtaining a second set of ADC samples generated by the ADCbased on the analog signals.
 20. The user equipment of claim 19 furthercomprises: means for determining an output timing of the second set ofADC samples based at least in part on the determined first ADC outputtiming.
 21. The user equipment of claim 19 further comprises means forgenerating an ADC input clock based on the system clock.
 22. The userequipment of claim 21, wherein generating the ADC input clock based onthe system clock further comprises: means for multiplying a rate of thesystem clock by a first predetermined value; and means for dividing themultiplied system clock rate by a second predetermined value.
 23. Theuser equipment of claim 22, wherein generating the ADC input clock basedon the system clock further comprises: means for routing the systemclock to the ADC based on low voltage differential signaling (LVDS). 24.The user equipment of claim 19 further comprises means for generating astart signal indicating a starting point of capturing the second set ofADC samples.
 25. The user equipment of claim 24 further comprises meansfor generating the start signal with a predetermined time-delayaccording to the system clock.
 26. The user equipment of claim 25further comprises means for synchronizing the start signal with an ADCoutput clock.
 27. The user equipment of claim 26 further comprises meansfor generating a capturing sample clock for capturing the second set ofADC samples, based on combining the synchronized start signal and theADC output clock using an AND gate.